signtool sign returns error 0x800700C1

Fri, 19 Jan 2018 17:54:49 +0000

I was trying to sign an .appx package that I created with the Desktop App Converter. However signtool returned the following error: Sign returned error: 0x800700C1 For more information, please see http://aka.ms/badexeformat

Sadly signtool doesn’t return more detailed information, even when passing the debug switch:

So what’s going on?

How to use a comma in the Publisher field when using the Desktop App Converter

Tue, 16 Jan 2018 14:55:51 +0000

When using the Desktop App Converter there’s no need to sign the resulting .appx packages with your own code signing certificate when you submit them to the Store.

However if you want to test the package on a different machine or distribute it to test users you may want to sign the .appx with a certificate.

One option is to use the -sign parameter, in this case the Desktop App Converter generates a code signing certificate and signs the package with it. Although easy to use, it’s not very convenient if you want to distribute the .appx as you need to add the certificate to the Trusted People certificates store (for each user). See Run the Packaged App in the documentation.

If you want to sign the .appx package with a trusted certificate (e.g. issued by a trusted certificate authority such as DigiCert) you need to make sure that you pass the subject (the CN) from your code signing certificate to the Desktop App Converter (using the -Publisher parameter).

UWP on Remko's Blog

signtool sign returns error 0x800700C1

How to use a comma in the Publisher field when using the Desktop App Converter